Humans have eaten earth, on purpose, for more than 2,300 years. They also crave starch, ice, chalk, and other unorthodox items of food. Some even claim they are addicted and "go crazy" without these items, but why? Sifting through extensive historical, ethnographic, and biomedical findings, Sera L. Young creates a portrait of pica, or nonfood cravings, from humans' earliest ingestions to current trends and practices. In engaging detail, she describes...